Noise reduction control targeted to a three-dimensional space is based on the assumption that both a noise source and a control sound source can be approximated to point sound source groups. With regard to non-rotating system noise in industrial equipment, power generating facilities, and the like, noise reduction target sounds can be approximated by a low sound range. This has also been demonstrated in actual equipment. Consider, however, rotor blade noise accompanying rotation represented by large-engine noise. In this case, depending on a driving situation, a sound source is not always a non-directional point sound source. When a noise source having such an unknown directivity characteristic is approximated by a non-directional point sound source, the effect of noise reduction control is reduced.